This project consists essentially in a systematic investigation of the precise chemical structure of glycolipids which are formed in the course of each discrete step of their biosynthesis in oncogenic cells as compared to non-oncogenic cells. Our approach will consist in incubating homogenates of cells transformed by viruses and the corresponding non-transformed cells with various precursor glycolipids of well established structure and labeled with radioactivity in the glycosyl unit which will act as receptor of the additional glycosyl residue from the donor sugar nucleotides. It will then be possible to trace the radioactive receptor glycosyl unit and to establish by the method of permethylation the precise position or positions of the newly formed linkage(s) in the product glycolipid even when the amount of product is extremely small.